A Japanese activist who was taken captive in Iraq in April filed a lawsuit against the government Tuesday, seeking 5 million yen in damages on the grounds that his ordeal was caused by Japan’s dispatch of troops to the country.

Nobutaka Watanabe, 36, a member of a nongovernmental organization, filed the suit at the Tokyo District Court, maintaining he was captured in Iraq because of the deployment of Self-Defense Forces troops there and that his captivity made him suffer “mental and physical pain.”

Watanabe also sought a court decision to declare that he has no obligation to pay the roughly 23,000 yen that the Foreign Ministry is seeking from him to cover part of the costs of his plane flight back to Japan.

Watanabe, together with freelance journalist Junpei Yasuda, 30, was captured by a militant group near Baghdad on April 14 and was released three days later.

According to the lawsuit, the group told their captives that they had seized them because they were citizens of a country that had dispatched troops to Iraq.

Three other Japanese civilians were held hostage by a militant group in Iraq that month and were later released unharmed. The group initially threatened to kill the hostages unless Japan pulled its troops out of Iraq.

After filing the lawsuit, Watanabe said he hoped his legal action would lead to a full-fledged debate on whether the troop deployment violates Japan’s pacifist Constitution. Article 9 of the Constitution renounces war and the use of force as a means of settling international disputes.

Watanabe, who had entered Iraq in February, said that, from what he saw, the southern Iraqi city of Samawah was “far from being a noncombat zone.” He said it was clear that there were violations of the Constitution and of the special law on reconstruction assistance to Iraq that limits the activities of the Self-Defense Forces to noncombat zones.

Opponents of the SDF dispatch have been filing lawsuits at the Tokyo District Court since mid-March, stating that the SDF dispatch violates the Constitution. Watanabe is the 56th person to file a lawsuit of this kind.